a) Your best friend doesn't remember your birthday.
Does you best friend remember your birthday?
b) They don't study English.
Do they study English?
c) The teacher doesn't give a lot of homework.
Does the teacher give a lot of homework?
d) Julia and Pedro don't make lunch every day.
Do Julia and Pedro make lunch every day?
Como você tem afirmativas no presente, o seu auxiliar é o DO (I, YOU, THEY, WE) ou o DOES (HE, SHE, IT). Para torná-las negativas, você só adiciona o NOT, que pode vir contraído (don't/doesn't), sempre concordando com o pronome.